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[check mark] New Discovery for Type 1 Diabetes


[check mark] Dietary Supplements GMP News


[check mark] Antidepressants and Decreased Bone Density


Food and Drug Administration Finds No Strong Link Between Tomatoes and Reduced Cancer Risk

A US Food and Drug Administration (FDA) review has found only limited evidence for an association between eating tomatoes and a decreased risk of certain cancers. Several studies have reported an association between the consumption of tomatoes or lycopene, an antioxidant that gives tomatoes their red hue, and a decreased risk of some cancers, particularly prostate cancer. For foods and dietary supplements to be labeled with such health claims, the FDA must review and approve these claims based on the available scientific evidence.


Researchers describe the agency's November 2005 evaluation of the scientific evidence linking tomatoes or tomato-based foods, lycopene, and reduced cancer risk. They found no evidence that tomatoes reduced the risk of lung, colorectal, breast, cervical, or endometrial cancer. However, there was very limited evidence for associations between tomato consumption and reduced risk of prostate, ovarian, gastric, and pancreatic cancers. Based on this assessment, the FDA decided to allow qualified health claims for a very limited association between tomatoes and these 4 cancers. Their analysis found no credible evidence that lycopene, either in food or in a dietary supplement, was associated with reduced risk of any of the cancers evaluated.


For prostate cancer, for example, the FDA issued this statement: "Very limited and preliminary scientific research suggests that eating one-half to one cup of tomatoes and/or tomato sauce a week may reduce the risk of prostate cancer. [The] FDA concludes that there is little scientific evidence supporting this claim."


Source: Journal of the National Cancer Institute


Gene Discovered for Type 1 Diabetes in Children

Pediatrics researchers have identified another gene variant to the 4 genes already discovered that raise a child's risk for type 1 diabetes (juvenile diabetes). As investigators continue to pinpoint genes contributing to diabetes, their eyes are on providing a scientific basis for designing better treatments and preventive measures for the disease.


In type 1 diabetes, the immune system destroys insulin-producing beta cells in the pancreas and makes patients dependent on frequent insulin injections to keep the body's blood sugar under control. Researchers think there are perhaps as many as 15 or 20 additional genes thought to interact with each other in the disease.


In the discovery phase of the study, the investigators examined the genomes of 1,046 children with type 1 diabetes. These DNA samples came from patients and families followed up in pediatric diabetes clinics in Philadelphia and 4 Canadian cities. Specifically, the researchers compared the genomes of 563 patients with type 1 diabetes with those of 1,146 matched control subjects. Those results were combined with those obtained from an independent analysis of 483 family trios, in which the genomes of a child with the disease and both parents were examined.


The researchers confirmed the 4 previously identified locations for genes contributing to type 1 diabetes but also uncovered a new type 1 diabetes locus on chromosome 16, occupied by a gene called KIAA0350. The team then replicated this discovery in yet another independent cohort of 1,333 children with the disease from the Type 1 Diabetes Genetics Consortium, which includes children of European descent in Europe, North America, and Australia, as well as in 390 additional type 1 diabetes family trios from Canada.


The gene implicated in the current research, KIAA0350, is known to be active almost exclusively in immune cells. Although scientists do not currently know the exact function of the protein the gene encodes, other research has predicted that it produces a protein called C-type lectin that is located on the surface of immune cells and binds to groups of sugars in the body.


Although much research remains to be done, better understanding of the disease process may guide doctors to new and improved therapies. The researchers note, "If we know the gene pathways that give rise to type 1 diabetes, we hope to intervene early in life with targeted drugs or cell therapies to prevent the disease from developing."


Source: Nature


Dietary Supplement Good Manufacturing Practice (GMP) News

Dietary supplement manufacturers will have to be in compliance with newly issued-and long anticipated-dietary supplement good manufacturing practices by June 2008, whereas the smallest firms will have until June 2010.


The Food and Drug Administration posted the regulation for advanced display on the Federal Register on June 22.


The final rule "includes requirements for establishing quality control procedures, designing and constructing manufacturing plants, and testing ingredients and the finished product," the Food and Drug Administration notes. It also includes "requirements for record keeping and handling consumer product complaints." The rule does not apply to suppliers or producers of raw ingredients, but instead places the onus of GMP compliance completely on manufacturers.


Although the rule applies to dietary supplements and not dietary ingredients, any dietary ingredient used in a supplement product will be required to pass "100%" identity testing. Firms will be required to verify the identity of any components that are dietary ingredients and confirm the identity of "other components."




Commonly Prescribed Antidepressants Associated With Lower Bone Density in Older Men and Women

The class of antidepressant medications known as selective serotonin reuptake inhibitors (SSRIs) may be associated with an increased rate of bone loss in older men and women.


Selective serotonin reuptake inhibitors treat depression by inhibiting the protein that transports serotonin, a neurotransmitter involved in sleep and depression, according to background information in the articles. This protein has recently been discovered in bone as well, raising the possibility that SSRIs may affect bone density and the risk of fracture. Selective serotonin reuptake inhibitors account for approximately 62% of antidepressant prescriptions in the United States and are often prescribed to the elderly.


The researchers studied 2,722 older women (average age, 78.5 years) from 1997 to 1999. Then and approximately 5 years later, researchers measured women's total hip bone density and also that of 2 subregions.


A total of 198 (7.3%) of the women were SSRI users, 118 (4.3%) took tricyclic antidepressants, and 2,406 (88.4%) took neither (those who took both were not included in the analysis). After the researchers adjusted for other factors affecting bone density and antidepressant use, including depression severity and calcium supplement use, bone mineral density at the hip decreased 0.82% in SSRI users. This compared with a decrease of 0.47% among those who used tricyclic antidepressants and also in those who did not take any antidepressants. Higher rates of bone loss were also observed at the 2 hip subregions among SSRI users.


In this cohort, use of SSRIs is associated with increased rates of hip bone loss. Although some of this association may have occurred because women who were prescribed SSRIs were different from those who were not prescribed SSRIs, "further investigation of SSRI use and rates of change in bone mineral density in other populations with longer follow-up is warranted given the recent description of serotonin transporters in bone."


In a related study on 5,995 men 65 years and older (average age, 73.7 years), the men's bone density at the hip, including subregions, and at the base of the spine was measured between 2000 and 2002. Participants were asked to bring all medications to their clinic visit, where they were also given a physical examination and asked about other health and lifestyle factors.


A total of 160 (2.7%) men reported using SSRIs, 99 (1.7%) reported using tricyclic antidepressants, and 52 (0.9%) reported using trazodone, a third type of antidepressant. Total hip bone mineral density was 3.9% lower among SSRI users than among men who did not use any antidepressants. Similarly, spine bone mineral density was 5.9% lower among SSRI users than among nonusers. There was no significant difference in either hip or spine density between men who took tricyclic antidepressants or trazodone and those who did not take antidepressants.


"These associations are biologically plausible and clinically important," the authors conclude. "Because SSRI use is prevalent in the general population, our findings have a potentially important public health impact. If confirmed, people using SSRIs might be targeted for osteoporosis screening and preventive intervention."


Source: Arch Intern Med. 2007;167:1240-1245, 1246-1251.